Astronomers have seen a shockwave through space generated by an exploding star for the first time, and say it could reveal how elements like gold and silver are formed.
The international team captured the earliest minutes of two exploding stars, both of which were hundreds of times larger than our sun.
They only saw the shockwave from the smaller of the two old, red supergiants, because the wave from the larger one didn't make it to the surface.
The findings were reported in The Astrophysical Journal today, and author Dr Brad Tucker from the Australian National University compared the phenomenon to a nuclear bomb, "only much bigger and no one gets hurt".
Stars explode when their fuel runs low and the core collapses. The resultant supernova is brighter than the rest of its galaxy and can shine for weeks.
In fact, they're so bright they can be seen from distant galaxies, which is helpful for astronomers on Earth to get a peek into the workings of outer space.
As the core of the supernova collapses to form a neutron star, energy bounces back as a shockwave which travels between 30,000 and 40,000km/s.
It causes the nuclear fusion which creates heavy elements such as gold, silver and uranium.
The larger supergiant had a radius 460 times that of our sun, "so large that the shockwave did not travel all the way to the surface" according to Dr Tucker.
The smaller was less than half that, at 270 times the radius of our sun.
Researchers from the University of Notre Dame, the Space Telescope Science Institute, the University of California Berkeley, and University of Maryland saw the shockwave as a peak of light from the explosion in the first few days.
They say the explosions will give them more information about how elements humans need to survive such as iron, zinc and iodine are created.